Since 1965 a small consulting bureau has been maintained at the Institute of Child Health, London, under the Human Adaptability Program of the International Biological Program (IBP). The bureau has acted as an international information and training center on all aspects of growth studies. Now as the IBP enters the final Phase III the need is seen for a survey volume presenting a comprehensive view of population differences in growth and physique. Approval has been granted by the IBP Central Office for publication of the book by the Cambridge University Press as one of the final synthesis volumes of the IBP. The research and preparation of the volume will take a minimum of two years, one of which has financial support from the Royal Society of London. The book itself will cover all known results from IBP/HA studies on growth and also major results from other growth studies carried out in the last ten years. The emphasis will be on compilation and organization of published and unpublished data collected by many investigators on the growth of children of different races living in various geographical and climatic regions. Though the book will be a compendium of growth data, it will not be a mere tabulation. Discussions and comparisons will be presented to increase our knowledge of the processes of growth. The volume is intended to serve as a reference work for investigators in child health, child development, and nutrition and should be a major contribution to those fields. Though primarily concerned with physical rather than mental growth, the work will be of fundamental source value to workers in the mental development field particularly those investigating ethnic differences.